When a Republican lawmaker publicized a U.S. intelligence assessment that secretive North Korea may have the knowhow to put a nuclear warhead on a missile, it caused a political bombshell in Washington and the Obama administration quickly played it down. But the revelation actually contained little new.

The intelligence agency making the assessment had publicized a similar conclusion before, and so had other weapons experts although many still dispute it. So why did it cause such a stir?

The clearest reason is that came after weeks of dire threats from Pyongyang, warning of a nuclear war against the U.S. That's fueled speculation over whether the impoverished, isolated nation is truly capable of translating its decades of developing ballistic missiles and atomic technology into a lethal attack.

But it could also have reflected political sensitivities. Intelligence agencies don't know for sure whether North Korea can launch a nuclear warhead. But even if they were certain, they might not want to acknowledge that fact. Doing so could be viewed as de facto recognition of North Korea as a nuclear weapons state _ something that Pyongyang wants but the international community won't grant as it seeks to get the North to honor previous commitments to abandon nuclear weapons.

So the U.S. government faces a dilemma. Accentuate the threat, and it could feed into the authoritarian regime's notorious brinkmanship. Take the threat lightly, and Washington could be accused of putting the U.S. and its allies at risk.

That's given rise to some confusion.

``It would help if the U.S. government would get its message on the North Korea threat straight,'' Jeffrey Lewis, director of the East Asia Nonproliferation Program at the Monterey Institute of International Studies wrote in a blog this week. ``Ignorance can breed unreasoning fear, so divulging more information might not be a bad idea.''

The North's blood-curdling rhetoric is widely viewed as an attempt at extracting concessions as it seeks aid and security guarantees, more than four years after it withdrew from multi-nation aid-for-disarmament negotiations. U.S. officials say the North doesn't appear to be readying its forces. In fact soldiers have been mobilized to help plant spring crops.

But the Obama administration has mounted a robust response, sending B-52 and B-2 bombers on exercises at the Korean Peninsula, and mobilizing missile ship-borne defenses in the region and a land-based system on the Pacific territory of Guam. North Korea is reportedly readying a test launch of an intermediate-range missile that could shoot over Japan.

The Pentagon has also announced it is boosting missile interceptors in Alaska. That shows that after a successful long-range rocket launch in December, and North Korea's third nuclear test in February, Washington is gearing up for the likelihood the North will before long pose a direct threat to the continental U.S.

Yet, actually coming out and saying whether North Korea now has the ability to fire a nuclear weapon _ most feasibly against South Korea and Japan, where the U.S. has military bases _ remains a sensitive matter.

Republican Rep. Doug Lamborn last week read aloud at a congressional hearing what he said was an unclassified paragraph from a secret, seven-page Defense Intelligence Agency report that it has ``moderate confidence'' that North Korea has nuclear weapons capable of delivery by ballistic missiles, but that the weapon was unreliable.

The Pentagon moved swiftly to play down an assessment from its own intelligence wing, and the top U.S. intelligence official, James Clapper, explained Thursday the passage in question had been mislabeled, and was in fact classified. He said there's disagreement within the intelligence community about the assessment and the DIA has a ``higher confidence level'' than other agencies about it.

But the DIA assessment didn't appear to break much new ground.

At a March 2011 hearing of the Senate Armed Service Committee, then-DIA director Lt. Gen. Ronald Burgess told lawmakers: ``The North may now have several plutonium-based nuclear warheads that it can deliver by ballistic missiles and aircraft as well as by unconventional means.''

The likelihood of that being true has grown since the February nuclear test when the North claimed it used detonated ``a miniaturized and lighter nuclear device with greater explosive force.''

Bruce Bennett, RAND Corp. senior defense analyst specializing in North and South Korea, concurs there's a ``reasonable chance'' that North Korea can mount a nuclear warhead on at least for its shorter-range missiles, although it remains very unlikely that it has an intercontinental missile that can deliver a nuclear weapon to the U.S., which is more technically challenging.

A Washington-based diplomat familiar with assessments on the North's capabilities agreed. The diplomat, who divulged the sensitive information on condition that his nationality not be identified, said that since its second underground nuclear test in 2009, the North has probably been able to nuclear-arm missiles like the Nodong, which has an 800-mile range and could hit Japan, and Scud missiles of shorter range that can hit South Korea.

James Schoff, a former senior adviser on East Asia policy at the Pentagon, and now at the Carnegie Endowment for International Peace, said defense planners in Japan have resigned themselves to the possibility that North Korea could fire a nuclear missile, and it's stirred a debate there about whether Japan should develop its own independent, long-range strike capability _ using aircraft, cruise missiles or ballistic missiles. Last October, South Korea reached an agreement with the U.S. to more than double the range of Seoul's ballistic missiles to counter the growing North Korean threat.

Ultimately, no one knows for sure what North Korea's nuclear weapons capability is. It banished U.N. nuclear inspectors in 2008, and the last U.S. scientist to have had access to its only known nuclear facility was in late 2010.

In his testimony to lawmakers this week, Clapper went so far as to say ``neither we nor the North Koreans'' know whether the nuclear weapons capability, if they have it, will actually work.

But he conceded that the North has been in the nuclear business for 50 years and it's probably just a matter of time before its reclusive regime acquires technologies that would put the U.S. within its range. (AP)